Typically the oil pan of an automotive vehicle is secured to the engine block by bolts extending through a flange of the oil pan into threaded bores in the block. An isolator rail locates the bolts. A gasket forms an oil-tight seal between the oil pan and the block. What is needed is a tool for preassembling the oil pan, gasket and isolator rail to provide proper alignment thereof and to insure proper guidance of the bolts into the threaded bores of the block.